Integrin alpha 2 is one of twelve Integrin alpha subunits that associates with the beta 1 subunit. Integrin alpha 2 beta 1 (VLA-2) is one of twelve integrin family adhesion receptors that share the beta 1 subunit. It is one of six very late antigens expressed on activated T cells. Divalent cations and intracellular (inside-out) signaling convert it to its most active, extended, and open conformation. a2b1 binds to Collagen types I, II, and III, Laminin, Decorin, E‑Cadherin, and Collectin molecules such as C1q. Platelet a2b1, also called GPIa, cooperates with GPVI to coordinate platelet collagen binding and activation. Adhesion is enhanced by crosstalk with Syndecan-1 or HGF R/c-Met and antagonized by crosstalk with Integrin alpha 1 beta 1. a2b1 is additionally expressed on select hematopoietic and non‑hematopoietic cells.
